KCET 2014 Biology Solved Paper

The group of mice injected with a mixture of live R strain and heat-killed S strain of pneumococci, neither of which is lethal by itself. Some of the mice which received the mixture also died of pneumonia. The live S strain as well as R strain bacteria were recovered from the dead mice. It was found that only DNA was responsible for transformation because when DNA was treated with DNase (which degraded DNA), transformation was not possible.